Indifferent electrode in electrosurgical procedures and method of use

ABSTRACT

A disposable indifferent electrode easily contoured to body surfaces including an electrode electrolyte assembly in which the electrode is relatively small in size yet provides very effective electrical contact between it and the body surface by virtue of an interposed electrolyte composition of predetermined characteristics; and, in surgical diathermy, a method of conducting high frequency radio waves to ground.



1. An indifferent electrode for use in electrosurgical procedures and easily contoured to body surfaces which comprises an electrode-electrolyte assembly including an electrode and an electrolyte composition in which the electrode is an electrically conductive means having at least 0.038 square inch surface thereof in essentially complete contact with said electrolyte composition having at least 2.0 square inches of its conductive surface adaptable to be applied in essentially complete conductive contact with the skin of a patient and having a thickness of at least 10 mils to thus space any part of said conductive means from the skin, said thickness being at least about 165 mils when the conductive element surface area is between about 0.038 and 0.10 square inch, said electrically conductive means, in turn, having a means for electrically connecting said electrode.
 2. The indifferent electrode of claim 1 wherein the electrically conductive means is a disc.
 3. The indifferent electrode of claim 1 wherein the electrically conductive means is a wire.
 4. The indifferent electrode of claim 1 wherein the electrically conductive means is a flexible sheet of stainless steel and the electrolyte is an alkali metal sulfate.
 5. The indifferent electrode of claim 4 wherein the electrolyte is an aqueous composition containing, by weight, from about 0.5 percent to about an aqueous saturated solution of alkali metal sulfate.
 6. The indifferent electrode of claim 5 wherein the electrolyte is an aqueous composition containing, by weight, from about 5 percent to about 20% alkali metal sulfate.
 7. The indifferent electrode of claim 6 wherein the alkali metal sulfate is sodium sulfate.
 8. The indifferent electrode of claim 4 having means defining a low profile cup shaped non-conductive cavity which opens to the body surface and having said flexible sheet of conductive metal electrode at the base of the cavity and coplanar to said base, said electrolyte composition being contained in said cavity and completely overlying and in contact with the surface of the electrode away from said base.
 9. The indifferent electrode of claim 8 wherein the electrolyte comprising an alkali metal sulfate and a sponge-like cellular matrix is an aqueous highly viscous semisolid composition comprising, by weight, from abouT 3 percent to about an aqueous saturated solution of alkali metal sulfate, and a small but effective amount of a water-soluble, water-swellable mucilage, said sponge-like cellular matrix containing said sulfate-mucilage blend uniformly distributed throughout its interstices.
 10. The indifferent electrode of claim 9 wherein the mucilage is a neutralized, water-soluble water-swellable carboxypolymethylene present in the concentration of about 0.2 percent to about 5.0 percent, based upon the total weight of the electrolyte composition.
 11. The indifferent electrode of claim 8 wherein the electrode is a flexible sheet of stainless steel which is in electrical contact with a conductive means passing through the base of the cup-shaped member and to a ground external to the cup.
 12. The indifferent electrode of claim 11, wherein the aqueous highly viscous semisolid electrolyte composition substantially fills the interior of said cup member and has a thickness at least as great as the depth of said cup member.
 13. The indifferent electrode of claim 12 wherein the thickness of said aqueous highly viscous semisolid electrolyte composition exceeds the depth of said cup member.
 14. The indifferent electrode of claim 13 wherein a removable protective covering overlies the open end of the cup member, said covering being a sheet material having a raised portion overlying the semisolid electrolyte protruding from the cup member.
 15. The indifferent electrode of claim 14 having an apertured flexible and resilient sheet carrying said cup member, the surface of said flexible and resilient sheet in coplanar relationship to the outer surface of the base of the cup member being substantially greater than that of the outer surface of the base member and having a pressure sensitive adhesive coating thereon for adhering to a body surface.
 16. The indifferent electrode of claim 15 having conductive securing means projecting through the aperture in said flexible and resilient sheet, through the base of said cup member, and securely attached to the flexible sheet of conductive metal.
 17. The indifferent electrode of claim 16 wherein the conductive securing means is securely attached to the flexible sheet of conductive metal by projecting through said thin flexible sheet, and the said securing means is a conductive metal snap fastener.
 18. The indifferrent electrode of claim 17 wherein the stud portion of said snap fastener passes sequentially through the flexible sheet of conductive metal, the cup member and the flexible, resilient adhesive-bearing sheet and terminates in locking engagement with the mating socket of said snap fastener.
 19. The indifferent electrode of claim 18 wherein the aqueous highly viscous semisolid composition has an aperture therein through which a non-conductive rivet passes and terminates in locking engagement in the hollow neck portion of said stud of said snap fastener, thus mounting the semi-solid composition on the flexible sheet of conductive metal and in immediate contact therewith.
 20. The indifferent electrode of claim 15 further including a cover sheet releasably secured to said adhesive coating and means securing said protective covering to said cover sheet.
 21. The indifferent electrode of claim 1, wherein the electrolyte composition has on its skin an electrical capacitor insulator capable of capacitively coupling under electrosurgical conditions.
 22. The indifferent electrode of claim 21, wherein said insulator is at the interface of the electrically conductive means and the electrolyte composition.
 23. The indifferent electrode of claim 21, wherein, in addition, a similar insulator is at the interface of the electrolyte composition and the electrically conductive means.
 24. The indifferent electrode of claim 23, wherein the insulator is a thin polymer film.
 25. The indifferent electrode of claim 24, wherein the insulator is a saran film.
 26. The indifferent electrode of claIm 1, wherein the electrolyte composition is an electrolyte-containing fabric.
 27. The indifferent electrode of claim 26, wherein the fabric is unwoven cotton fabric.
 28. The indifferent electrode of claim 1, wherein the electrolyte composition contains an inert filler.
 29. The indifferent electrode of claim 28, wherein the inert filler is powdered talc.
 30. In surgical diathermy, a method of conducting high frequency radio waves to ground which comprises placing against and coplanar to the body surface a flexible sheet of conductive metal electrode, said sheet surface opposite and nearer said body surface having an area in the range of about 0.5 square inch to about 10 square inches, and interposing in direct and essentially complete contact with said opposed surfaces of electrode and body an electrolyte composition of substantially uniform thickness, said thickness being in the range of about 62 mils to about 500 mils.
 31. The method of claim 30 wherein the said sheet surface opposite and nearer said body surface has an area in the range of about 2 square inches to about 5 square inches.
 32. The method of claim 30 wherein the flexible sheet of conductive metal is stainless steel and the electrolyte is an alkali metal sulfate.
 33. The method of claim 32 wherein the alkali metal sulfate is sodium sulfate.
 34. The method of claim 33 wherein the electrolyte is an aqueous composition containing, by weight, from about 0.5 percent to about an aqueous saturated solution of alkali metal sulfate.
 35. The method of claim 34 wherein the electrolyte is an aqueous composition containing, by weight, from about 5 percent to about 20 percent alkali metal sulfate.
 36. The method of claim 26 wherein the alkali metal sulfate is sodium sulfate. 